Research integrity is essential in clinical trials research, because decisions about the safety and efficacy of medical therapies must be based on unbiased and credible evidence. However, there has been little systematic investigation of research integrity in clinical trials. Whereas research integrity is often treated as a dichotomy (presence or absence of misconduct), we propose a multi-level definition that recognizes that there are problems in research integrity that do not fall to the level of misconduct. The proposed research is a two-year project to develop a method to measure multi-level research integrity in pharmacologic clinical trials. Using focus groups and interviews with trialists, we will develop a self-administered questionnaire that asks investigators about research integrity problems in clinical trials. Having developed the questionnaire, we will mail it and a measure of investigators' conflicts of interest to 500 authors of published clinical trials. We will also code the quality of the trials' methods from the published reports. Using these data, we will examine whether levels of research integrity are associated with clinical trial outcomes, quality of trial methods, and investigators' financial conflicts of interest. The questionnaire we propose would provide a tool for field studies of research integrity. Moreover, by examining whether problems of research integrity are associated with study outcomes, we will obtain important information about the social costs of problems in research integrity. Finally, a finding that financial conflicts of interest are associated with violations of research integrity would provide a possible explanation for the troubling observation that study outcomes are associated with conflicts of interest.